Air-compressor.



No. 819,655. PATENTED MA Yl, 1906. E. HILL.

AIR COMPRESSOR.

APPLICATION FILED JAN. 13, 1905.

EBEN'EZER HILL, OF NORWALK, CONNECTICUT. Am-com n'izsson.

Specification of Letters Patent.

Patented May 1, 1906.

Application filed January 13, 1906 Seria1No.2 40,918.

To all whom it may concern.- 7

Be it known that I, EBENEZER HILL, a citizen of the United States, residi at Norwalk, in the county'of Fairfield and tate of Conv necticut, have invented a new and useful Air- Compressor, of which the following is a specification.

Air or gas compressors are frequently connected so that a high-pressure compressor will receive the who e or a part of the discharge of a low-pressure compressor. These are so arran ed that when the pressure beyond the hil-PIGSSUIG compressor becomes excessive a valve in the connection between the discharge of the low and the intake of the high pressure compressors is shut and .the passage through the connection from one compressor to the other is closed. If the piston of the high-pressure compressor is mechanically joined with the piston of the low-pressure compressor, as is common, and' the low-pressure compressor continues to operate, the high-pressurecompressor will,with the valve in the connection closed, exhaust air or gas from'its intake and force it into its discharge. As a result of this heat is developed to such-a degree that the lubricant becomes volatilized and the gas is liable to be ignited and cause a disastrous explosion.

The object of this invention is to so construct and arrange the valves and the connections of the high-pressure compressor that its piston will automatically be rendered ineffective without interrupting its movement when the connection between the compressors is closed, and this danger of overheating and explosion'be avoided.

In the embodiment of the invention that is illustrated the piston of the high-pressure compressonis mechanically joined with the piston of the low-pressure compressor, and the discharge of the latter is connected with the intake of theformer by an ordinary connection. In this connection is a valve that is normally open, but which is closed when the pressure beyond the hi h-pressure compressor becomes excessive, y means of the movement of a piston in a cylinder that is connected with the discharge of the highpressure compressor, and the high-pressure compressor is provided with intake-valves.

that are automatically held open, and thus become inoperative, when the passage.

through theconnection from one compressor to the other is closed, thereby temporarily 2 putting the high-pressure cylinder out of action without affecting the movement of its piston.

Figure 1 of the views represents a side elevation of so much of a high-pressure com- 6 pressor and low -pressure compressor and the valves; and connections as is necessary to illustrate the-invention. Fig. 2 shows, on eatlyenlar ed scale, a section of one of the intake va ves of the high pressure compressor, whichis held open so as to render the pistonineffective when the valve in the connection between the com ressors is closed. Fig. 3 shows, on enlarge scale, the valve in the connection between the compressors, the weight for opening this valve, and the piston for closing it when the pressure beyond the high-pressure compressor becomes excessive.

The low-pressure compressor 1 may be of 7 any type for compressing air or gas. The piston of this compressor is adapted to be connected with the piston of a steam-cyhnder or any other means for giving the iston a reciprocatory motion by means of t e rod 2. Air or gas is drawn into this compressor through the intake 3 and is forced out' throu h the discharge 4 in the ordinary manner, t e intake-valves 5 and the dischargevalves 6 being of common construction. 8

The highressure compressor]: maybe any type and its piston may be*- ]01I1ed with the piston of the low-pressure com ressor, as usual. The intake 8 of the big -pressure disc arge from the low-pressure compressor, so that the airor gas which 1s taken 'mto the high-pressure compressor and is forced out w fitting 11, and in that cylinder is attached to a iston 15, the stem 16 of which above the cylinder is connected with a lever 17, provided with a weight 18, the wei .ht and lever being arranged to tend to ho d the valve 0 en.

The cylinder above the fitting is connected with the discharge of the high-pressure coma pipe 19. This pipe communicates wit the cylinder below the plston m compressor is connected by a pipe 9 with the 9 such manner that when the pressure in the discharge of the high-pressure com ressor becomes excessive that pressure will e exerted through the ipe a ainst the lower side of the piston and l' the ever and weight and close the valve. When this valve is closed, communication between the discharge of the lowressure compressor and the intake of the 'gh-pressure compressor is cut oif, and to prevent the high-pressure compressor from exhausting air or gas from'the intake and forcing it orwardly when the pressure is exoessive and the valve is closed what for convenience will be termed skip-valves are rovided for the high-pressure compressor.

hese valves are of such construction that when the valve inthe connection between the compressor is closed and the continued movement of the piston in the high-pressure com-- pressor tends to draw the air or gas from and ower the pressure in the high-pressure intake theywill remain open and'temporaril possibly for only part of a stroke and per aps for several strokes, put the high-pressure compressor out of efiectipve action.

In the form of the invention illustrated the intake-valves 20 fof the high-pressure compressor are ski valves. Each of these valves is provi ed with a disk 21, that is adapted to open inwardly from and close out-. wardly against a seat in the wall 22 of the com ressor in the usual manner. has a stem 23, that i'ssup'ported by a hub 24 and is provided with a head 25. A spring 26 is arranged to thrust betweenthe head and a portion of the hub and draw the valve to its seat. A. plu 27 is screwed into the wall 28 of the head 0 the high-pressure (glinder, and in this lug is a piston 29. spring 30 thrusts etwcen this piston and the end. of the ing in such-manner as to tend to force the piston toward the end of the stem of the valve-disk. There is a passagp 31 between the chamber the plugland t e intake-passa e 32in the head of t e high-pressure cylin er, s6; that the pressure on the intake side of the valve-disk is'always exerted against the piston in the plug in oppositionpto the spring. As long as the ressure inthe mtakepassage remains norma the piston is forced away from the head of the stem of the valvedisk. Should thepressure in this intake-v assage become lowered, as by the continued reciprocation of the high pressure PISt OII when the valve closes thecommunlcatlon between" the discharge of the low-pressure compressor and the Intake of the highressure compressor, then the s ring Wlll orce the piston against the head 0 the stem of the valve-disk and hold the disk away from its seat. While the intake-valves are held open, whether for only a part of a stroke or a single stroke at intervals or a number of strokes in succession, air iulsates back and forth past these open inta e-valves in such manner as This disk forcing to rehder the piston ineffective for torcin air forwardly into the discharge. As a res this action the space between the choke-valve in the connectionv between the compressors and the high-pressure piston will not be extof' hausted of airthat is,-the air in that space a will not be exhausted and portions of it advanced beyond the high-pressure compressor so that the pressure in that s ace will be low and the air therein at the ow pressure be forced forwardly and raised to the relatively high degree of compression beyond the highpressure compressor, and thus sufficient heat be developed to volatilize the lubricating-oil and greases and ignite the gas thus generated and causean explosion.

The invention claimed is I 1. An apparatus for compressin air having a low-pressure compressor, a igh-pressure compressor, a connection between the disohar e of the lowressure compressor and the inta e of the hig -pressure compressor, a

valve in the connection between the compressors that is closed by an abnormally high pressure beyond the high-pressure compressor, and an inlet-valve connected with the high-pressure compressor that is held open, when the pressure between itself and the valve in the connection between the compressors drops belownormal as a result'of the closing of the connection-valve, so asto render the high-pressure iston ineffective for air forward w en the connectionvalve 1s closed, substantially as specified.

2. Anapparatus for compressing air havroo ing a low-pressure compressor, a high-pressure compressor a connection betweenthe dischar eof the owressure compressor and the inta e of the hig -pressure compressor, a valve for closing the connection between the compressors, means for holdin the valve open, a piston connected with an adaptedto move the valve, a duct forming a communication between the discharge of the high.- pressure compressor and the cylinder containing the valveiston whereby excessive pressure in the disc argp of the high-pressure compressor will cause t e piston to move and close the valve in the connection, and an'inletvalve connected with the hi h-pressure compressor that is held open w en the pressure etwcen itself and the valve in the connection between the compressors drops below normal as a result of the closing of the connectionvalve so as to render the high-pressure iston ineffective for forcin air forward w en the connection-valve is c osed, substantially as specified.

. 3. Anapparatus for compressing air hav ing a low-pressure cylinder a piston in the low-pressure. cylinder, a high-pressure cylinder, a piston in the high-pressure cylinder, said pistons being mechanically connected, a connection between the discharge of the lowpressure cylinder and the intake of the highrec" , pressure cylinder, a valve in the connection etween the cylinders that is closed by an abnormally high pressure beyond the high-pressure cylinder, and an inlet-valve connected with the high-pressure cylinder that is held open when the pressure between itself and the valve in the connection between the cylinders drops below normal as a result of the closing of the connection-valve so as to render the high-pressure piston ineflective for forcing air forward when the connectionvalve is closed, substantially as specified.

4. Thecombination of an air-com ressing cylinder a piston movable in the cy inder, a

valve for closing the intake of the cylinder that is closed by an abnormally high "ressure beyond the cylinder, and an inlet-va ve connected with the cylinder that is held open when the pressure between itself and the valve in the intake drops below normal as a result of the closing of the intake-valve so as to render the piston ineffective for forcing air forward when the intake-valve is closed, sub stantially as specified.

Y. EBENEZER HILL.-

Witnesses:

J. E. SLATER,

S. M. STEVENS. 

